Generally, when MPLS forwarding is performed on a Provider (P) node in a service provider network, the P node will directly search an MPLS forwarding table according to an ingress tunnel label of an MPLS packet, and then directly sends the table replacing the tunnel label. Such forwarding is one-to-one, and the one-to-many forwarding is impossible.
The present MPLS multicasting is performed on an ingress service Provider Edge (PE) node in a Layer 2 Virtual Private Network (L2VPN) multicasting mode of an MPLS ingress; after an original packet enters the PE node, the PE node directly encapsulates a tunnel label and a pseudo-wire label and sends them from a corresponding multicast egress by means of the network deployment of a Virtual Private LAN Service (VPLS).
The currently common forwarding on the P node includes steps as follows:
1. after an MPLS packet is received, an MPLS table is searched through a tunnel label of the MPLS packet;
2. a corresponding MPLS table entry is found; the tunnel label of an egress is included in the table, a label action is label switching, and the egress position is pointed out; and
3. the tunnel label of the packet is directly replaced with the tunnel label of the egress in the MPLS table, and is sent out from the egress, so as to complete the label switching forwarding at the P node.
The currently common multicasting on the VPLS PE node includes steps as follows:
1. A user side packet enters the PE node;
2. The PE node searches a Media Access Control (MAC) address table according to an MAC address of the user side packet, and determines a VPLS multicast group; and
3. According to the setting of a multicast grout table entry, a pseudo-wire label and a tunnel label are added for the user side packet and sent from each port group corresponding to the multicast group.
It can be seen from above that in related art, there is no such a technology for performing point-to-multipoint multicast forwarding aiming at the P node, because it is unable to perform point-to-multipoint forwarding on the P node, 1+1 or 1+N protection cannot be realized on the P node.